package SV_AUTH_HASH_MIGHT;

public class Fixed {
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String userName = request.getParameter("userName");
        String md5 = getMd5(userName);
       ...
    }
    public static String getMd5(String str)
    {
        try {
            MessageDigest md = MessageDigest.getInstance("SHA3-256");
            byte[] messageDigest = md.digest(str.getBytes());
            //...
        }
}
